In typical OCT and OFDR systems, the spatial resolution of the measurement is determined by the range of a continuous sweep of a tunable laser source. Therefore, the measurement time of an OCT or OFDR system is limited by how quickly the laser can scan the wide wavelength ranges—for example, 100 nm at a rate of 100 kHz. The spatial resolution of the measurement is also limited by the technical limit of how wide a wavelength range that a single laser can scan. The current state-of-the-art tunable lasers operating at 1310 nm or 1550 nm can scan, at most, a 100-150 nanometer (nm) range.